Usefulness of Sonazoid contrast-enhanced ultrasonography for hepatocellular carcinoma: comparison with pathological diagnosis and superparamagnetic iron oxide magnetic resonance images

Review of dynamic contrast-enhanced ultrasound guidance in ablation therapy for hepatocellular carcinoma

Local ablative techniques-percutaneous ethanol injection, microwave coagulation therapy and radiofrequency ablation (RFA)-have been developed to treat unresectable hepatocellular carcinoma (HCC). The success rate of percutaneous ablation therapy for HCC depends on correct targeting of the tumor via an imaging technique. However, probe insertion often is not completely accurate for small HCC nodules, which are poorly defined on conventional B-mode ultrasound (US) alone. Thus, multiple sessions of ablation therapy are frequently required in difficult cases. By means of two breakthroughs in US technology, harmonic imaging and the development of second-generation contrast agents, dynamic contrast-enhanced harmonic US imaging with an intravenous contrast agent can depict tumor vascularity sensitively and accurately, and is able to evaluate small hypervascular HCCs even when B-mode US cannot adequately characterize the tumors. Therefore, dynamic contrast-enhanced US can facilitate RFA electrode placement in hypervascular HCC, which is poorly depicted by B-mode US. The use of dynamic contrast-enhanced US guidance in ablation therapy for liver cancer is an efficient approach. Here, we present an overview of the current status of dynamic contrast-enhanced US-guided ablation therapy, and summarize the current indications and outcomes of reported clinical use in comparison with that of other modalities.

Sonazoid-enhanced ultrasonography for the diagnosis of an intrapancreatic accessory spleen: a case report

We report a case of an intrapancreatic accessory spleen in 59-year-old man, in which contrast-enhanced sonography (US) using Sonazoid, a second-generation contrast agent, was useful for the diagnosis. Sonazoid-enhanced US could prove both hypervascularity and the existence of reticuloendothelial cell systems in the mass, which is the key to the diagnosis of an accessory spleen. Sonazoid-enhanced US might become a standard imaging technique for the diagnosis of an accessory spleen.

APASL and AASLD Consensus Guidelines on Imaging Diagnosis of Hepatocellular Carcinoma: A Review

Consensus guidelines for radiological diagnosis of hepatocellular carcinoma (HCC) have been drafted by several large international working groups. This article reviews the similarities and differences between the most recent guidelines proposed by the American Association for Study of Liver Diseases and the Asian Pacific Association for the Study of the Liver. Current evidence for the various imaging modalities for diagnosis of HCC and their relevance to the consensus guidelines are reviewed.

Assessment of hepatocellular carcinoma by contrast-enhanced ultrasound with perfluorobutane microbubbles: comparison with dynamic CT

OBJECTIVE

The aim of this study was to evaluate tumour vascularity and Kupffer cell imaging in hepatocellular carcinoma (HCC) using contrast-enhanced ultrasonography (CEUS) with Sonazoid (perfluorobutane) and to compare performance with dynamic CT.

METHODS

We studied 118 nodules in 88 patients with HCC. HCC was diagnosed as a hyperenhancement lesion in the arterial phase with washout in the portal phase on dynamic CT or by percutaneous biopsy. We observed tumour vascularity at the early vascular phase (10-30 s after contrast injection) and Kupffer imaging at the post-vascular phase (after 10 min).

RESULTS

Detection of vascularity at the early vascular phase was 88% in nodules that were found to be hypervascular on dynamic CT and 28% in hypo-/isovascular nodules; the detection of local recurrence nodules was 92%. The detection of vascularity was significantly lower in nodules >9 cm deep than in those ≤9 cm deep, but was not affected by tumour size. The detection of tumours at the post-vascular phase on CEUS was 83% in nodules with low density in the portal phase on dynamic CT and 82% in nodules with isodensity. The rate did not depend on the severity of underlying liver disease; rates decreased in nodules deeper than 9 cm, those smaller than 2 cm in diameter and in iso-enhancing nodules at the early vascular phase of CEUS.

CONCLUSION

CEUS with Sonazoid is a useful tool for assessing the vascularity of HCC and is equal to that of dynamic CT; however, the detectability of HCC vascularity is affected by location.

Improved diagnosis of well-differentiated hepatocellular carcinoma with gadolinium ethoxybenzyl diethylene triamine pentaacetic acid-enhanced magnetic resonance imaging and Sonazoid contrast-enhanced ultrasonography

AIM

  Two new imaging modalities have been developed recently that are directed at the focal liver lesions: gadolinium ethoxybenzyl diethylene triamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and Sonazoid contrast-enhanced ultrasonography (CEUS). We investigated the usefulness of these modalities for the diagnosis of small (<2 cm), well-differentiated hepatocellular carcinoma (HCC).

METHODS

  A total of 15 nodules from 13 patients, which were histologically diagnosed as well-differentiated HCC, were subjected to this study. Lesions that showed hypervascularity in the arterial phase and washout in the portal or late non-hemodynamic phase were regarded as HCC in the dynamic studies of all imaging modalities.

RESULTS

  By multidetector computed tomography (MDCT), six of 15 (40%) nodules were diagnosed as HCC. Gd-EOB-DTPA-enhanced MRI diagnosed HCC in nine of the 15 (60%) nodules. Of the nine nodules that were not diagnosed by MDCT, four could be diagnosed by Gd-EOB-DTPA-enhanced MRI. In Sonazoid CEUS, 10 of 15 nodules (67%) were diagnosed as HCC. Four of nine nodules that could not be diagnosed as HCC by MDCT, were diagnosed by Sonazoid CEUS. A total of 11 of the 15 (73%) nodules were diagnosed as HCC by Gd-EOB-DTPA-enhanced MRI and Sonazoid CEUS in addition to MDCT.

CONCLUSION

  Gd-EOB-DTPA-enhanced MRI and Sonazoid CEUS had greater diagnostic value for small, well-differentiated HCC than did conventional MDCT.

Strategy of treatment for hepatocellular carcinomas with vascular infiltration in patients undergoing hepatectomy

BACKGROUND AND OBJECTIVES

Vascular infiltration (VI) is an important prognostic factor for hepatocellular carcinoma (HCC) and predictive parameters are necessary to preoperatively decide treatment strategies in patients with HCC.

METHODS

Relationships between presence and degree of VI in the portal and hepatic veins and bile duct, and post-hepatectomy survival were examined in 271 HCC patients who underwent hepatectomy.

RESULTS

VI was observed in 81 patients (30%). Disease-free and overall survival rates was significantly lower in patients with VI than in patients without VI, and became poorer according to the degree of infiltration (P < 0.01). Multiple, increased size, non-meeting of Milan criteria, irregular macroscopic findings and increased PIVKA-II levels were associated with degree of VI in portal vein (P < 0.01). Increased size and increased PIVKA-II level were associated with degree of VI in hepatic vein (P < 0.05). Non-meeting of Milan criteria was associated with degree of infiltration in bile duct (P = 0.034). Survival was significantly better following anatomical resection than with non-anatomical resection and, furthermore, survival was better with surgical margins >5 mm than with shorter margins in patients who underwent non-anatomical resection.

CONCLUSION

Adequate extent of operative procedures, but not limited resection with short margins, is useful when predictive parameters associated with VI are observed.

Contrast-enhanced harmonic EUS with novel ultrasonographic contrast (Sonazoid) in the preoperative T-staging for pancreaticobiliary malignancies

OBJECTIVE

Sonazoid is a new second-generation microbubble contrast for ultrasonography. In this pilot study, the diagnostic role of contrast-enhanced harmonic imaging endoscopic ultrasonography (CH-EUS) with Sonazoid was prospectively evaluated in preoperative T-staging of pancreaticobiliary malignancies.

PATIENTS AND METHODS

Patients with suspected pancreaticobiliary malignancies underwent CH-EUS by a single examiner. After the lesions were observed carefully with conventional harmonic imaging EUS (H-EUS), CH-EUS was performed with intravenous injection of Sonazoid. A reviewer who was blinded reviewed the recordings of H-EUS and CH-EUS and assessed the T-staging. The accuracy of H-EUS and CH-EUS for T-staging was compared to the results of surgical histopathology in patients who underwent surgery.

RESULT

Twenty-six patients underwent surgical resection and could be included in the study. The final diagnosis were pancreatic cancer in 11, bile duct cancer in 7, gallbladder cancer in 4 and ampullary cancer in 4. The overall accuracy of H-EUS and CH-EUS for T-staging were 69.2 (18/26) and 92.4% (24/26), respectively (p < 0.05). There were disagreement in six cases between H-EUS and CH-EUS. CH-EUS staged correctly in all of these six cases, whereas H-EUS misdiagnosed the depth of invasion in one case of gallbladder cancer and one case of ampullary cancer, and invasion of portal vein in two cases of pancreatic cancer and two cases of bile duct cancer.

CONCLUSION

The depth of invasion of biliary cancer and vascular invasion of pancreatic and biliary cancer could be demonstrated more clearly with CH-EUS compared to H-EUS. CH-EUS has the potential to improve the diagnostic accuracy of preoperative T-staging of pancreaticobiliary malignancies.

Progress in the development of ultrasound-mediated gene delivery systems utilizing nano- and microbubbles

Recently, ultrasound-mediated gene delivery with nano- and microbubbles was developed as a novel non-viral vector system. In this gene delivery system, microstreams and microjets, which are induced by disruption of nano/microbubbles exposed to ultrasound, are used as the driving force to transfer genes into cells by opening transient pores in the cell membrane. This system can directly deliver plasmid DNA and siRNA into cytosol without endocytosis pathway. Therefore, these genes are able to escape from degradation in lysosome and result in enhancing the efficiency of gene expression. In addition, it is expected that ultrasound-mediated gene delivery using nano/microbubbles would be a system to establish non-invasive and tissue specific gene expression because ultrasound can transdermally expose to target tissues and organs. This review focuses on the current ultrasound-mediated gene delivery system using nano/microbubbles. We discuss about the feasibility of this gene delivery system as novel non-viral vector system.

Radiofrequency ablation guided by contrast harmonic sonography using perfluorocarbon microbubbles (Sonazoid) for hepatic malignancies: an initial experience

AIM

Conventional contrast harmonic sonography has the technical problem of a short enhancement time during targeting of hepatic malignancies for radiofrequency (RF) ablation. This study investigated the effectiveness of contrast harmonic sonographic guidance using perfluorocarbon microbubbles (Sonazoid) during RF ablation of hepatic malignancies.

MATERIALS AND METHODS

Nodules were detected on contrast-enhanced computed tomography, but could not be resolved clearly by B-mode sonography. Sixty-six patients (51 men, 15 women; mean age, 65.8 years) with 108 hepatic malignancies were enrolled. Fifty-one patients with hepatocellular carcinoma and 15 patients with liver metastases were treated by RF ablation guided by contrast harmonic sonography using perfluorocarbon microbubbles for a target lesion identified as a defect image after the administration of contrast medium.

RESULTS

The maximal diameters of all tumours ranged from 0.7 to 3.5 cm (mean +/- SD, 1.7 cm +/- 0.9) on sonography. Complete tumour necrosis was achieved by a single session of RF ablation in 62 (94%) of the 66 patients, while two sessions were required for the remaining four (6%) patients. The average number of treatment sessions was 1.1 +/- 0.3. In the post-vascular phase, 105 (97%) of a total of 108 malignant hepatic tumours were depicted as a defect with a margin. Clinical courses have been satisfactory without any signs of local tumour progression during 1-12 months of follow-up (mean, 4.3 months).

CONCLUSION

Using perfluorocarbon microbubbles, contrast harmonic sonographic-guided RF ablation is an efficient approach for guiding further ablation of hepatic malignancies that are not clearly demarcated by B-mode sonography.

Intra-operative freehand real-time elastography for small focal liver lesions: "visual palpation" for non-palpable tumors

BACKGROUND

Freehand real-time elastography (RTE) has seldom been used to visualize abdominal organs due to their complicated structure and difficulty in freehand compression. We describe a novel, intra-operative imaging system for performing freehand RTE of the liver.

METHODS

An RTE system was designed using a spatial, cross-correlation method equipped with a feedback function that checks the quality and quantity of the external compression. Intra-operative freehand RTE was performed for 27 adenocarcinomas, 18 hepatocellular carcinomas (HCCs), and 11 benign lesions after routine B-mode intra-operative ultrasonography (IOUS). Elasticity images were classified into 4 types, from type A (more or comparable strain relative to the background) to type D (no strain), according to the degree of strain contrast with the surrounding liver. We then evaluated the compliance of the RTE findings with the pathologic diagnosis.

RESULTS

RTE images were obtained for all the lesions except for 1 metastatic adenocarcinoma. Fourteen of the 18 HCCs were classified as type B or C, with a sensitivity of 83%, a specificity of 76%, and an accuracy of 61%, while 22 of the 26 adenocarcinomas were classified as type D, with a sensitivity of 85%, a specificity of 86%, and an accuracy of 86%. For 15 lesions, clear images were difficult to obtain using B-mode IOUS, whereas RTE visualized clearly the differences in elasticity.

CONCLUSION

Our new RTE system facilitated the successful freehand RTE of liver lesions in an intra-operative setting, enabling "visual palpation" during liver surgery and serving as a supportive modality for B mode IOUS.

Contrast enhanced ultrasound of hepatocellular carcinoma

Sonazoid (Daiichi Sankyo, Tokyo, Japan), a second-generation of a lipid-stabilized suspension of a perfluorobutane gas microbubble contrast agent, has been used clinically in patients with liver tumors and for harmonic gray-scale ultrasonography (US) in Japan since January 2007. Sonazoid-enhanced US has two phases of contrast enhancement: vascular and late. In the late phase of Sonazoid-enhanced US, we scanned the whole liver using this modality at a low mechanical index (MI) without destroying the microbubbles, and this method allows detection of small viable hepatocellular carcinoma (HCC) lesions which cannot be detected by conventional US as perfusion defects in the late phase. Re-injection of Sonazoid into an HCC lesion which previously showed a perfusion defect in the late phase is useful for confirming blood flow into the defects. High MI intermittent imaging at 2 frames per second in the late phase is also helpful in differentiation between necrosis and viable hypervascular HCC lesions. Sonazoid-enhanced US by the coded harmonic angio mode at a high MI not only allows clear observation of tumor vessels and tumor enhancement, but also permits automatic scanning with Sonazoid-enhanced three dimensional (3D) US. Fusion images combining US with contrast-enhanced CT or contrast-enhanced MRI have made it easy to detect typical or atypical HCC lesions. By these methods, Sonazoid-enhanced US can characterize liver tumors, grade HCC lesions histologically, recognize HCC dedifferentiation, evaluate the efficacy of ablation therapy or transcatheter arterial embolization, and guide ablation therapy for unresectable HCC. This article reviews the current developments and applications of Sonazoid-enhanced US and Sonazoid-enhanced 3D US for diagnosing and treating hepatic lesions, especially HCC.

Contrast-enhanced harmonic ultrasound imaging in ablation therapy for primary hepatocellular carcinoma

The success rate of percutaneous radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) depends on correct targeting via an imaging technique. However, RF electrode insertion is not completely accurate for residual HCC nodules because B-mode ultrasound (US), color Doppler, and power Doppler US findings cannot adequately differentiate between treated and viable residual tumor tissue. Electrode insertion is also difficult when we must identify the true HCC nodule among many large regenerated nodules in cirrhotic liver. Two breakthroughs in the field of US technology, harmonic imaging and the development of second-generation contrast agents, have recently been described and have demonstrated the potential to dramatically broaden the scope of US diagnosis of hepatic lesions. Contrast-enhanced harmonic US imaging with an intravenous contrast agent can evaluate small hypervascular HCC even when B-mode US cannot adequately characterize tumor. Therefore, contrast-enhanced harmonic US can facilitate RF ablation electrode placement in hypervascular HCC, which is poorly depicted by B-mode US. The use of contrast-enhanced harmonic US in ablation therapy for liver cancer is an efficient approach.